Popular conventional methods of assembling LCD panels are those in which facing two glass substrates are aligned, then they are pressed by a pressing machine or by a vacuum pack method, then the sealing material patterned in advance on at least one of the glass substrates is cured by heat or by light (ultraviolet rays). The above vacuum pack method is that the facing two glass substrates are airtightly packed in a bag made of soft material, then the facing two glass substrates are pressed by the shrinking pressure of the bag when the air in the bag is exhausted.
In order to obtain a proper and precise cell gap of the LCD panels, so called spacers such as approximately 5 .mu.m diameter balls made of polymer resin or glass, or approximately 5 .mu.m diameter glass fibers are sprayed (dispersed) on at least one of the facing two glass substrates in advance. As to the material for sealing the facing two glass substrates, heat curing type or light (ultraviolet rays) curing type materials are used. The chief ingredient of these materials is epoxy resin. The sealing material is then patterned by a screen printing method or by a dispenser method on one of the two facing glass substrates.
Then the facing two glass substrates are aligned precisely by an image recognition system. Then, in order to obtain the uniform cell gap of substantially the same dimension as the diameter of above described spacers, the sealing material patterned on the substrate is cured while the facing two glass substrates are pressed by the pressing machine, or the sealing material is cured after the facing two glass substrates are pressed by the vacuum pack method.
However, in the conventional methods described above, there is the problem of occurrence of gap defect that the cell gap becomes locally narrower at the point where foreign matter sticks, and also there is the problem of occurrence of scratch defect due to the foreign matter on the glass substrates. Furthermore there is the problem that it is difficult to realize a uniform cell gap because the glass substrates often deform since pressing them evenly is difficult. And also, in the method of using pressing machine, the facilities become large, then the facility cost and the large space are disadvantageous. Moreover, in the vacuum pack method, there are problems that indirect material cost is high and loss from work inefficiency are large.